JPS5812330B2 - Materials that remember pressure - Google Patents

Description

[Detailed Description of the Invention] The present invention involves processing and pressurizing a Hotchler-type metal compound containing Pd, Sn, and Mn, and measuring the strength of the magnetic force caused by the disordered alignment of the atoms in the combined process. It involves a material that remembers the applied pressure.

Alloys called Heusler-type metal compounds containing metals such as Pd, Sn, and Mn are known as alloys that exhibit ferromagnetism even though they do not contain any ferromagnetic elements.

Although academic research has been conducted on Heusler-type alloys for some time, their application as practical materials has been lacking.

The present invention is a practical method in which the Heusler alloy is processed to make the atomic arrangement of the alloy irregular, thereby changing the magnetic properties.Furthermore, the original 7 arrangement is maintained permanently unless external factors are added, and pressure can be memorized. There is a need to obtain suitable materials.

First, Pd, Mn, and Sn with a high purity of 99.9% or more are weighed as raw materials to form an alloy with a composition of Pd2MnSn, and then melted in an argon-filled high-frequency melting furnace to create a Heusler alloy ingot. .

Next, from the alloy ingot, #l sample was ground into 300 mesh powder, and this powder was heated to 300°C.
Four types of samples, #2 sample, #3 sample, and #7 sample, were prepared by annealing in vacuum at temperatures of , 400 °C, and 800 °C for 5 hours.

The measurement results of the thermomagnetic characteristics of the relationship between the magnetization strength σ and the temperature T of these samples are shown in FIG.

From the figure, when Pd2MnSn alloy is crushed into powder, the magnetization strength σ of the alloy decreases significantly, but #l, #2,
The numbers increase in the order of #3 and #7.

That is, the magnetism is recovered by annealing at 650°C.
It can be seen from the above that the magnetization strength σ of the powder sample pulverized to 300 mesh by annealing for 5 hours or more has the same value as the alloy before powder, and is completely recovered.

The first sample was made into a powder of 300 mesh or less after Heusler-type alloy was annealed at 600°C for IO days and slowly cooled, and the second sample was annealed at 600°C for 1 hour and immediately water-cooled, and the second sample was 200 mesh. FIG. 2 shows the thermomagnetic properties of four types of samples: a third sample as a powder below, and a fourth sample as a powder below 300 mesh.

From this result, the strength of magnetization is significantly reduced by crushing the Heusler alloy.

FIG. 3 is an X-ray diffraction pattern of the fourth sample measured using Ou as an X-ray target and a detector slit width of 0.2 degrees.

As shown in the figure, the weaker diffraction lines disappear and the higher the scattering angle, the wider the lines become.

At this time, the lattice constants etc. are shown in Table 1. In general, the reason for the broadening of X-ray diffraction lines during cold working is due to the scattering angle of X-rays, l/
When 2 is θ, one is due to the size of the crystal grain which is proportional to l/cosθ, and the other is due to the distortion of the crystal grain which is proportional to janθ.

Here, the crystal plane (Ilt), (2
26), (420), each putter”/■1
/cosθ, tanθ are calculated as shown in Table 2.

From this table, it can be said that the broadening of the X-ray diffraction line is caused by the distortion of the crystal grains.

As explained above, by processing or applying pressure to a Heusler-type alloy, the disorder of the original 7 arrangement of the alloy is promoted, and the strength of magnetization changes significantly.

Therefore, if we know the strength of magnetization due to disturbance of the original 7 arrangement of a Heusler type alloy that has been processed and pressurized, we can conversely determine the pressing force.

Moreover, since the alloy has changed its original 7 arrangement, the strength of magnetization does not change even if pressure is applied, so it can be used as a material for pressure memory elements.

As an example of the pressure memory material of the present invention, P
After melting the d2MnSn type alloy, it is ground to 300 mesh and annealed in vacuum at 800° C. for 12 hours to obtain pressure memory element 7 material.

Here, this alloy powder lgr was put into a mold with a diameter of 22 mm filled with alumina powder, 5 tons, 10 tons at room temperature,
After pressing with a pressure P of 25 tons for 15 hours, the alloy powder was increased from the mold, and the external magnetic field H was 11.5 kilogauss and 1.0 loggauss in liquid nitrogen.
Figure 4 shows the measurement of the magnetization strength σ.

It can be seen from this figure that there is a correlation between the applied pressure P and the magnetization strength σ.

Therefore, by measuring the magnetization strength σ, the magnitude of the applied pressure P can be determined, and its application as a pressure memory element material can be found.

The memory of this type of memory element material can be erased by changing the H-h arrangement from irregular to regular.

As described above, the Heusler type alloy is extremely effective as a material for memorizing pressure, and can be applied to various pressure sensors.

[Brief explanation of the drawing]

Figures 1 and 2 are thermomagnetic characteristics diagrams of various Heusler type alloy powders of the present invention, and Figure 3 is the crystal plane (400) and (22) of Pd2MnSn, the Heusler type alloy powder of the present invention.
0), and FIG. 4 is a diagram showing the relationship between pressure and magnetization strength in an example of the present invention.

Claims (1)

[Claims] 1. Chemical formula X2TZ [where X is palladium Pd, [. A pressure memory material made of a Heusler type metal compound represented by manganese (Mn) and Z (tin (Sn)).